Packages

case class Statistics(sizeInBytes: BigInt, rowCount: Option[BigInt] = None, attributeStats: AttributeMap[ColumnStat] = AttributeMap(Nil)) extends Product with Serializable

Estimates of various statistics. The default estimation logic simply lazily multiplies the corresponding statistic produced by the children. To override this behavior, override statistics and assign it an overridden version of Statistics.

NOTE: concrete and/or overridden versions of statistics fields should pay attention to the performance of the implementations. The reason is that estimations might get triggered in performance-critical processes, such as query plan planning.

Note that we are using a BigInt here since it is easy to overflow a 64-bit integer in cardinality estimation (e.g. cartesian joins).

sizeInBytes

Physical size in bytes. For leaf operators this defaults to 1, otherwise it defaults to the product of children's sizeInBytes.

rowCount

Estimated number of rows.

attributeStats

Statistics for Attributes.

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Serializable, Serializable, Product, Equals, AnyRef, Any
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Instance Constructors

  1. new Statistics(sizeInBytes: BigInt, rowCount: Option[BigInt] = None, attributeStats: AttributeMap[ColumnStat] = AttributeMap(Nil))

    sizeInBytes

    Physical size in bytes. For leaf operators this defaults to 1, otherwise it defaults to the product of children's sizeInBytes.

    rowCount

    Estimated number of rows.

    attributeStats

    Statistics for Attributes.

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  5. val attributeStats: AttributeMap[ColumnStat]
  6. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  7. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  8. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
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    @throws( classOf[java.lang.Throwable] )
  9. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  10. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  11. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  12. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  13. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  14. val rowCount: Option[BigInt]
  15. def simpleString: String

    Readable string representation for the Statistics.

  16. val sizeInBytes: BigInt
  17. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  18. def toString(): String
    Definition Classes
    Statistics → AnyRef → Any
  19. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  20. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
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    @throws( ... )
  21. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
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    @throws( ... ) @native()

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